JP5316324B2 - Imaging device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain focal point-detecting functions (capability to detect a maximum phase difference) equal to each other in length in two directions irrespective of a position on a screen by arranging focal point-detecting pixel arrays each having the same arrangement length on the screen densely and uniformly in the two directions. <P>SOLUTION: A plurality of focal point-detecting pixels receives luminous flux for detecting a focal point, and outputs focal point-detecting signals for detecting a focal point-adjusting state of an optical system by a pupil-splitting phase difference-detecting method. The plurality of focal point-detecting pixels constitute a plurality of focal point-detecting pixel arrays, which in turn are arranged in a plain-woven pattern substantially over the whole imaging surface. The plain-woven pattern in one embodiment is the style in which parallel and perpendicular focal point-detecting pixel arrays, both being equal to each other in length, are mutually arranged in a high-dense manner. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an imaging element and an imaging apparatus.

  There is known an image pickup device in which focus detection pixels using a pupil division type phase difference detection method are arranged in the horizontal direction at the center of the image pickup device, and image pickup pixels are arranged around the focus detection pixel (for example, see Patent Document 1).

International Publication No. 2008/032820

  In the conventional imaging device described above, the focus detection pixels are arranged so as to form an array corresponding to a plurality of focus detection directions such as a horizontal direction and a vertical direction, but are long only in one direction. Can not be arranged as. Therefore, the horizontal and vertical focus detection pixel arrays are arranged long to improve the maximum phase difference detection capability as much as possible and to make them the same, and the horizontal and vertical focus detection pixel arrays are displayed on the screen. However, it was impossible to satisfy the requirement to arrange them uniformly and densely at the same time.

In the first aspect of the present invention, the imaging device is emitted by the optical system and receives an imaging light beam that forms an optical image and outputs an image signal, and a pair of focus detection sensors that pass through the optical system. Formed by a plurality of focus detection pixels that receive a light beam and output a focus detection signal for detecting the focus adjustment state of the optical system by a pupil division type phase difference detection method, a plurality of imaging pixels, and a plurality of focus detection pixels The plurality of focus detection pixels constitute a plurality of focus detection pixel rows, and the plurality of focus detection pixel rows are arranged according to a plain weave pattern over substantially the entire surface of the image pickup surface. The pixels are arranged over substantially the entire surface of the imaging surface except for pixel positions where a plurality of focus detection pixels are arranged.
In the invention described in claim 15, an image pickup apparatus includes an optical system, the image pickup element described in any one of claims 1 to 14, and a generation unit that generates image data based on an image signal obtained from the image pickup element. And a focus detection means for detecting the focus adjustment state of the optical system based on a focus detection signal obtained from the image sensor.
According to a sixteenth aspect of the present invention, there is provided an image pickup apparatus that receives an interpolation signal at a pixel position where a plurality of focus detection pixels are arranged and an optical system, an image pickup element according to the tenth aspect, and a plurality of image pickups near the pixel position. An interpolation means for performing interpolation based on an image signal output from a pixel, an image signal obtained from an image sensor, a generation means for generating image data based on an interpolation signal at a pixel position to be interpolated by the interpolation means, an optical system A focus detection unit that detects a focus adjustment state based on a focus detection signal obtained from the image sensor, and an image signal output from a plurality of imaging pixels in the vicinity of the pixel position includes a first focus detection pixel array and An image signal output from a plurality of imaging pixels arranged between the second focus detection pixel rows is included.

  According to the present invention, since the focus detection pixel arrays having the same array length can be arranged uniformly and densely in two directions on the screen, the same focus detection performance (in two directions regardless of the position on the screen) Maximum phase difference detection capability).

1 is a cross-sectional view illustrating a configuration of a digital still camera according to an embodiment of the present invention. It is a figure explaining the principle of a pupil division type phase difference detection method. FIG. 6 is an optical path diagram illustrating a state in which light rays from a point on the subject on the optical axis of the interchangeable lens pass through the exit pupil of the interchangeable lens and arrive at the imaging surface. It is the figure which showed an example of arrangement | positioning of the focus detection pixel array in the imaging surface of an image pick-up element. It is a figure explaining the high density property of the plain weave pattern. It is an enlarged view of the focus detection pixel array in the imaging surface of an image sensor. It is a front view which shows the detailed structure of an image pick-up element. It is a figure which shows the shape of the micro lens of an imaging pixel and a focus detection pixel. It is a front view of an imaging pixel. The figure which shows the spectral characteristic of a green pixel, a red pixel, and a blue pixel. It is a front view of a focus detection pixel. The figure which shows the spectral characteristic of a focus detection pixel. It is sectional drawing of an imaging pixel. It is sectional drawing of a focus detection pixel. It is a figure for demonstrating the mode of the imaging light beam which a focus detection pixel receives. It is a figure for demonstrating the mode of the imaging light beam which an imaging pixel receives. It is a flowchart which shows the imaging operation of a digital still camera. It is a figure which shows the relationship of the correlation amount C (k) with respect to the shift amount k of a pair of data. It is the figure which expanded the area | region where the focus detection pixel arrangement | sequence of a horizontal direction and a vertical direction adjoins in an image pick-up element. It is a front view which shows the detailed structure of an image pick-up element. It is a front view of a focus detection pixel. It is sectional drawing of a focus detection pixel. It is an enlarged view of the focus detection pixel array in the imaging surface of an image sensor. It is an enlarged view of the focus detection pixel array in the imaging surface of an image sensor. It is an enlarged view of the focus detection pixel array in the imaging surface of an image sensor. It is the figure which showed an example of arrangement | positioning of the focus detection pixel array in the imaging surface of an image pick-up element. It is a front view which shows the detailed structure of an image pick-up element.

--- First embodiment ---
As an image pickup apparatus having the image pickup device of the first embodiment, a lens interchangeable digital still camera will be described as an example. FIG. 1 is a cross-sectional view illustrating a configuration of a digital still camera 201 according to the first embodiment. The digital still camera 201 according to the first embodiment includes an interchangeable lens 202 and a camera body 203, and the interchangeable lens 202 is attached to the camera body 203 via a mount unit 204. An interchangeable lens 202 having various photographing optical systems can be attached to the camera body 203 via a mount unit 204.

  The interchangeable lens 202 includes a lens 209, a zooming lens 208, a focusing lens 210, a diaphragm 211, a lens drive control device 206, and the like. The lens drive control device 206 includes a microcomputer (not shown), a memory, a drive control circuit, and the like. The lens drive control device 206 includes drive control for adjusting the focus of the focusing lens 210 and the aperture diameter of the aperture 211, zooming lens 208, and focusing. In addition to detecting the state of the lens 210 and the aperture 211, the transmission of lens information (described later) and the reception of camera information (defocus amount, aperture value, etc.) are performed through communication with a body drive control device 214 (described later). The aperture 211 forms an aperture having a variable aperture diameter at the center of the optical axis in order to adjust the amount of light and the amount of blur.

  The camera body 203 includes an imaging element 212, a body drive control device 214, a liquid crystal display element drive circuit 215, a liquid crystal display element 216, an eyepiece lens 217, a memory card 219, and the like. In the imaging element 212, imaging pixels are two-dimensionally arranged, and focus detection pixels are incorporated in portions corresponding to focus detection positions (focus detection areas). Details of the image sensor 212 will be described later.

  The body drive control device 214 includes a microcomputer, a memory, a drive control circuit, and the like, and controls the drive of the image sensor 212, reads out the image signal and the focus detection signal, performs the focus detection calculation based on the focus detection signal, and the focus of the interchangeable lens 202. The adjustment is repeated, and image signal processing and recording, operation control of the digital still camera 201, and the like are performed. The body drive control device 214 communicates with the lens drive control device 206 through the electrical contact 213 to receive lens information and transmit camera information.

  The liquid crystal display element 216 functions as an electric view finder (EVF). The liquid crystal display element driving circuit 215 displays a through image by the imaging element 212 on the liquid crystal display element 216, and the photographer can observe the through image through the eyepiece lens 217. The memory card 219 is an image storage that stores an image captured by the image sensor 212.

  A subject image is formed on the light receiving surface of the image sensor 212 by the light beam that has passed through the interchangeable lens 202. This subject image is photoelectrically converted by the image sensor 212, and an image signal and a focus detection signal are sent to the body drive control device 214.

  The body drive control device 214 calculates the defocus amount based on the focus detection signal from the focus detection pixel of the image sensor 212 and sends the defocus amount to the lens drive control device 206. The body drive control device 214 processes the image signal from the image sensor 212 to generate image data, stores the image data in the memory card 219, and transmits the through image signal from the image sensor 212 to the liquid crystal display element drive circuit 215. The through image is displayed on the liquid crystal display element 216. Further, the body drive control device 214 sends aperture control information to the lens drive control device 206 to control the aperture of the aperture 211.

  The lens drive controller 206 updates the lens information according to the focusing state, zooming state, aperture setting state, aperture opening F value, and the like. Specifically, the positions of the zooming lens 208 and the focusing lens 210 and the aperture value of the aperture 211 are detected, and lens information is calculated according to these lens positions and aperture values, or a lookup prepared in advance. Lens information corresponding to the lens position and aperture value is selected from the table.

  The lens drive control device 206 calculates a lens drive amount based on the received defocus amount, and drives the focusing lens 210 to the in-focus position according to the lens drive amount. Further, the lens drive control device 206 drives the diaphragm 211 in accordance with the received diaphragm value.

  FIG. 2 is a diagram illustrating the principle of the pupil division type phase difference detection method. A plurality of focus detection pixels 111 are arranged on the imaging surface 110. The focus detection pixel 111 includes a microlens 112 and a pair of photoelectric conversion units 113 and 114. The pair of photoelectric conversion units 113 and 114 is projected by the microlens 112 onto the distance measuring pupil plane 120 at a distance d ahead of the imaging surface 110, thereby forming a pair of distance measuring pupils 123 and 124. In other words, the luminous flux of the ranging pupil 123 out of the luminous flux passing through the distance measuring pupil plane 120 at a distance d ahead of the imaging surface 110 is received by the photoelectric conversion unit 113 of the focus detection pixel 111, and the distance measuring pupil plane. Among the light beams that pass on 120, the light beam of the distance measuring pupil 124 is received by the photoelectric conversion unit 114 of the focus detection pixel 111. The relative shift amount (phase difference, image shift amount) between the image signal of the photoelectric conversion unit 113 in the array of the focus detection pixels 111 and the image signal of the photoelectric conversion unit 114 is an image on the imaging surface. Since it changes according to the focus adjustment state of the optical system to be formed, the focus adjustment state of the optical system can be detected by calculating this shift amount by processing a pair of image signals generated by the focus detection pixels. .

  The pair of distance measurement pupils 123 and 124 does not have a distribution obtained by simply projecting the pair of photoelectric conversion units 113 and 114, but is based on the light diffraction effect according to the aperture diameter (substantially coincides with the pixel size) of the microlens 111. This is a distribution with a blurred background. In FIG. 3, when the pair of distance measurement pupils 123 and 124 are scanned in the alignment direction using the slit in the direction perpendicular to the alignment direction of the pair of distance measurement pupils 123 and 124, a pair of distance measurement pupil distributions 133 and 134 are obtained. . Due to the diffraction effect, the pair of distance measuring pupil distributions 133 and 134 have overlapping portions 135 at adjacent portions.

  As described above, in the pupil division type phase difference detection method, the image displacement amount on the imaging surface of the pair of images formed by the light flux passing through the pair of distance measurement pupils is detected and converted into the image displacement amount with a predetermined conversion. The coefficient is multiplied to convert to a defocus amount (focus adjustment state) in the optical axis direction. As the defocus amount increases, the image shift amount increases accordingly. This will be described with reference to FIG.

  FIG. 3 is an optical path diagram showing a state in which light rays 83 and 84 from a point on the subject on the optical axis 91 of the interchangeable lens pass through the exit pupil 90 of the interchangeable lens and arrive at the imaging surface 110. In FIGS. 3A and 3B, the image plane is largely defocused to the front side and the rear side of the planned focal plane (imaging plane 110). Light rays 83 and 84 exit from a point on the subject on the optical axis 91, pass through the center of the pair of distance measuring pupils, and are collected at points P01 and P02 on the optical axis 91. Points Pa 1 and Pa 2 are intersections of the light beam 83 and the imaging surface 110, and points Pb 1 and Pb 2 are intersections of the light beam 84 and the imaging surface 110.

  In FIG. 3A, the distance between the point P01 on the optical axis 91 and the imaging surface 110 is the defocus amount def1, and the distance between the point Pa1 and the point Pb1 on the imaging surface 110 is the image shift amount shft1. On the other hand, in FIG. 3C, the distance between the point P02 on the optical axis and the imaging surface 110 is the defocus amount def2, and the distance between the point Pa2 and the point Pb2 on the imaging surface 110 is the image shift amount shft2. As can be seen from FIGS. 3A and 3B, as the defocus amount increases and the actual image plane moves away from the imaging surface 110, the image shift amount increases. Therefore, in order to detect a large defocus amount, it is necessary to detect a large image shift amount, and in order to detect a large image shift amount, it is necessary to make the length of the focus detection pixel array as long as possible. .

  However, when the focus detection pixel arrays are arranged in a plurality of directions (horizontal direction and vertical direction), one of the arrays must be cut at the position where the arrays intersect, and the length of the focus detection pixel array is reduced. There is a restriction that it cannot be extended indefinitely. In order to perform focus detection in a plurality of directions (horizontal direction and vertical direction) at an arbitrary position on the screen, there is a demand for arranging a large number of focus detection pixel arrays in a plurality of directions as densely as possible on the imaging surface. Even based on the request, the length of the focus detection pixel array is restricted. If there is a large difference in multi-directional focus detection capability (large defocus detection capability), the focus detection performance differs depending on the direction in which the photographer holds the digital still camera 201, and the usability is poor. There is also a request to make the length of the detection pixel array uniform, and the length of the focus detection pixel array is also restricted based on this request.

  The arrangement mode of the focus detection pixel array that satisfies the above conditions is the plain weave pattern in the present embodiment. According to the plain weave pattern in the present embodiment, the lengths of the focus detection pixel arrays in the horizontal direction and the vertical direction can be made substantially the same, and a large number of focus detection pixel arrays in the horizontal direction and the vertical direction can be arranged at high density. .

  FIG. 4 is a diagram illustrating an example of the arrangement of focus detection pixel arrays on the imaging surface of the image sensor 212. The arrangement of the focus detection pixel array shown in FIG. 4 corresponds to the focus detection position (focus detection area) on the photographing screen of the interchangeable lens 202. In FIG. 4, the focus detection pixel array is shown innumerably as a horizontal bar-shaped region 351 and a vertical bar-shaped region 352. That is, the focus detection pixel array having a length L is arranged in a plain weave pattern in the horizontal direction and the vertical direction on substantially the entire surface of the rectangular imaging surface 110. The length and width of the focus detection pixel array refer to the length of the long side and the length of the short side of the focus detection pixel array. The length of the short side is substantially equal to the length of one side of the focus detection pixel. The horizontal direction and the vertical direction refer to the direction of one side of the rectangle of the outer shape of the imaging surface 110 and the direction of the other side perpendicular thereto. The plain weave pattern in the present embodiment is in contact with a repeating unit composed of a focus detection pixel array extending in the horizontal direction and a focus detection pixel array extending in the vertical direction either above or below it. It refers to an aspect in which the arrangement is repeated repeatedly at a high density.

  FIG. 5 is a diagram illustrating the high density of the plain weave pattern. In FIG. 5, for convenience of explanation, nine rows of focus detection pixel arrays having a length of L are represented as line segments ignoring the width, and do not completely intersect and contact each other in the horizontal direction and the vertical direction. Is arranged. In FIG. 5, a circle represents the middle point of each focus detection pixel array. Here, the focus detection pixel array “contacts” means that the focus detection pixels of another focus detection pixel array are arranged adjacent to each other without sandwiching the imaging pixel. The focus detection pixel array “intersects” means that the focus detection pixels of another focus detection pixel array are adjacent to each other without sandwiching the imaging pixel on both sides of one focus detection pixel in one focus detection pixel array. To be placed.

  In FIG. 5A, the horizontal and vertical focus detection pixel arrays are in contact with each other at end points. FIG. 5B is a diagram illustrating a state where the contact point is moved by rL from one end point of the focus detection pixel array in the horizontal direction and the vertical direction. FIG. 5C is a diagram showing a state where the contact point is moved L / 2 from one end point of the focus detection pixel array in the horizontal direction and the vertical direction. In addition, the density of the focus detection pixel array in each pattern increases as the area of the plurality of filled regions formed by being surrounded by the nine focus detection pixel arrays with circles is smaller.

The area S of the above-described filled region is represented by S = 2L ² in FIG. 5A and S = 4 · (L / 2) ² = L ² in FIG. 5C. Further, in FIG. 5B, it is expressed by the equation (1) with respect to 0 ≦ r ≦ 1, and when r = 0, 1, S has the maximum value 2L ² and is shown in FIG. 5A. examples and match, in the case of r = 1/2 S is consistent with the example shown the minimum value L ^2, and the FIG. 5 (c). That is, FIG. 5C shows a plain weave pattern in which the horizontal focus detection pixel array and the vertical focus detection pixel array having the same length are arranged at the highest density when the length L is constant. This shows the case of being done. In this embodiment, when r = 0, 1, that is, the mode shown in FIG. 5A is not included in the plain weave pattern, and is exemplified in FIGS. 5B and 5C. In addition, the mode in the case of 0 <r <1 is included in the plain weave pattern.
S = 2 · [(rL) ² + {(1−r) · L} ² ] = 4L {r− (1/2)} ² + L ² (1)

  An example of the arrangement of the focus detection pixel array shown in FIG. 4 follows the uniform and most dense aspect shown in FIG. 5C among plain weave patterns when the length of the focus detection pixel array is a constant L. It is a thing. When the size of the imaging surface is 36 mm horizontal and 24 mm vertical, the length of the focus detection pixel array is preferably about 2 mm to 8 mm.

6 is an enlarged view showing a portion A in FIG. In FIG. 6, the focus detection pixel arrays are slightly separated from each other so as not to be completely in contact with each other because of pixel interpolation processing described later. In FIG. 6, when each of a plurality of filled regions formed by the nine focus detection pixel arrays marked with the circles noted in FIG. 5C is represented by S _{1 to} S ₄ , The sum of the areas is S = L ² so as to be derived by substituting r = 1/2 into the above-described equation (1). Further, among the horizontal bar-shaped regions 351, the one located at the upper left of FIG. 6 is defined as a focus detection pixel array a1, and a vertical bar-shaped region 352 extending vertically from the side of the focus detection pixel array a1. Among them, the one extending downward is defined as a focus detection pixel array b1. A T-shaped array composed of the focus detection pixel arrays a1 and b1 is defined as a first array. A horizontal bar-shaped area 351 adjacent to the right side of the focus detection pixel array b1 is defined as a focus detection pixel array a2, and the vertical bar-shaped area 352 extending vertically from the side of the focus detection pixel array a2 extends upward. The existing one is defined as a focus detection pixel array b2. An array having an inverted T-shape constituted by the focus detection pixel arrays a2 and b2 is defined as a second array. The first and second sequences, is the center of the area S ₁ in mutually point symmetrical positional relationship to the point of symmetry. The plain weave pattern in the present embodiment is formed by repeatedly arranging the first array and the second array on the image sensor 212 while maintaining such a positional relationship.

  FIG. 7 is a front view showing a detailed configuration of the image sensor 212, and shows the details of the pixel arrangement by enlarging the vicinity of the portion B in FIG. Imaging pixels 310 are densely arranged on the imaging element 212 in a two-dimensional square lattice pattern. The imaging pixel 310 includes a red pixel (R), a green pixel (G), and a blue pixel (B), and is arranged according to a Bayer arrangement rule. For focus detection, vertical focus detection focus detection pixels 313a and 314a and horizontal focus detection focus detection pixels 313b and 314b having the same pixel size as the image pickup pixel are alternately arranged, and originally green pixels and blue pixels are used. They are continuously arranged on vertical and horizontal straight lines to be continuously arranged. In the vicinity where the vertical focus detection pixel array intersects with the horizontal focus detection pixel array, one focus detection pixel array (in this figure, the horizontal focus detection pixel array) is cut and an imaging pixel is disposed between them. Yes. In this way, by arranging the imaging pixels between the focus detection pixel arrays in the cutting unit, the performance at the intersection of pixel interpolation processing described later is improved.

  The focus detection pixels 313a, 313b, 314a, and 314b are arranged in a column in which B and G of the imaging pixel 310 are to be arranged. The focus detection pixels 313a, 313b, 314a, and 314b are arranged in a column in which the B and G of the imaging pixel 310 are to be arranged. An interpolation process for obtaining an image signal for imaging at the position of the focus detection pixel This is because the interpolation error of the blue pixel is less noticeable than the interpolation error of the red pixel due to human visual characteristics when an interpolation error occurs in FIG. The focus detection pixels 313b and 314b are configured by rotating the focus detection pixels 313a and 314a by 90 degrees, respectively.

  The imaging pixel 310 is designed in such a shape that the microlens 10 receives all the light flux that passes through the exit pupil diameter (for example, F1.0) of the brightest interchangeable lens. In addition, the focus detection pixels 313a, 313b, 314a, and 314b are designed in such a shape that the microlens 10 receives light beams that pass through a pair of predetermined regions of the exit pupil of the interchangeable lens.

  FIG. 8 is a diagram showing the shape of the microlens of the image pickup pixel and the focus detection pixel, and has a shape cut out in a square shape corresponding to the pixel size from a circular microlens 9 that is originally larger than the pixel size, A cross section in the direction of a diagonal line passing through the optical axis of the microlens 10 and a cross section in the direction of a horizontal line passing through the optical axis of the microlens 10 have shapes shown in FIG.

  As shown in FIG. 9, the imaging pixel 310 includes a rectangular microlens 10, a photoelectric conversion unit 11 whose light receiving area is limited by a light shielding mask described later, and a color filter (not shown). There are three types of color filters, red (R), green (G), and blue (B), and the respective spectral sensitivities have the characteristics shown in FIG. In the image pickup device 212, image pickup pixels 310 having respective color filters are arranged in a Bayer array.

  As shown in FIG. 11A, the focus detection pixel 313 has a rectangular microlens 10, a photoelectric conversion unit 13 whose light receiving area is limited by a light shielding mask described later, and an ND filter (neutral density filter) (not shown). However, the shape of the photoelectric conversion unit 13 whose light receiving area is limited by the light shielding mask is rectangular. Further, as shown in FIG. 11B, the focus detection pixel 314 includes a rectangular microlens 10, a photoelectric conversion unit 14 whose light receiving area is limited by a light shielding mask described later, and an ND filter, and receives light by the light shielding mask. The shape of the photoelectric conversion unit 14 whose region is limited is a rectangle. When the focus detection pixel 313 and the focus detection pixel 314 are displayed with the microlens 10 superimposed, the photoelectric conversion units 13 and 14 whose light receiving areas are limited by the light shielding mask are arranged in the vertical direction. The pair of focus detection pixels (313, 314) collectively refers to the pair of focus detection pixels (313a, 314a) and (313b, 314b).

  The focus detection pixels 313 and 314 are not provided with a color filter in order to perform focus detection for all colors, but instead are provided with the above-described ND filter that reduces the amount of incident light. The characteristics shown in FIG. That is, the spectral characteristics are obtained by adding the spectral characteristics of the green pixel, the red pixel, and the blue pixel shown in FIG. 10, and the light wavelength regions in which the focus detection pixels 313 a and 314 a exhibit high spectral sensitivity are green pixels, red pixels, and It covers the light wavelength region where the blue pixel shows high spectral sensitivity.

  The density of the ND filter is determined so that, for example, the output level of the focus detection pixel is 3/4 or less of the output level of the green pixel when the image sensor is exposed to white light. This is because vignetting of the focus detection light flux occurs in a region where the image height on the screen is high (a focus detection area at a position away from the optical axis 91), and the output balance of the pair of focus detection pixels (313, 314) is lost. Even when the output level of one focus detection pixel increases, the output level of the green pixel in the imaging pixel 310 is not exceeded.

  FIG. 13 is a cross-sectional view of the imaging pixel 310. In the imaging pixel 310, a light shielding mask 30 is formed in proximity to the imaging photoelectric conversion unit 11, and the photoelectric conversion unit 11 receives light that has passed through the opening 30 a of the light shielding mask 30. A planarizing layer 31 is formed on the light shielding mask 30, and a color filter 38 is formed thereon. A planarizing layer 32 is formed on the color filter 38, and the microlens 10 is formed thereon. The shape of the opening 30 a is projected forward by the microlens 10. The photoelectric conversion unit 11 is formed on the semiconductor circuit substrate 29.

  FIG. 14 is a cross-sectional view of the focus detection pixels 313 and 314. In the focus detection pixels 313 and 314, a light shielding mask 30 is formed in proximity to the focus detection photoelectric conversion units 13 and 14, and the photoelectric conversion units 13 and 14 have passed through the openings 30 b and 30 c of the light shielding mask 30. Receives light. A planarizing layer 31 is formed on the light shielding mask 30, and an ND filter 34 is formed thereon. A planarizing layer 32 is formed on the ND filter 34, and the microlens 10 is formed thereon. The shapes of the openings 30b and 30c are projected forward by the microlens 10. The photoelectric conversion units 13 and 14 are formed on the semiconductor circuit substrate 29.

  FIG. 15 shows a configuration of a focus detection optical system of the pupil division type phase difference detection method using the microlens 10. The portions of the focus detection pixels 313 and 314 are shown enlarged. In FIG. 15, the exit pupil 90 is set at a position of a distance d forward from the microlens 10 disposed on the planned imaging plane of the interchangeable lens 202 (see FIG. 1). This distance d is a distance determined in accordance with the curvature and refractive index of the microlens 10, the distance between the microlens 10 and the photoelectric conversion units 13 and 14, and is referred to as a distance measuring pupil distance in this specification. FIG. 15 also shows the optical axis 91 of the interchangeable lens, the microlens 10, the photoelectric conversion units 13 and 14, focus detection pixels 313 and 314, the photographing light beam 71, and the focus detection light beams 73 and 74.

  The distance measuring pupil 93 is formed by projecting the shape of the opening 30 b by the microlens 10. Similarly, the distance measuring pupil 94 is formed by projecting the shape of the opening 30 c by the microlens 10. In FIG. 15, for the sake of easy understanding, the areas of the distance measuring pupils 93 and 94 are shown. However, in reality, the shapes of the openings 30b and 30c are enlarged and projected and become blurred due to diffraction.

  FIG. 15 schematically illustrates five focus detection pixels adjacent to the photographing optical axis. However, in the focus detection pixel array in the peripheral portion of the screen, each photoelectric conversion unit has a corresponding distance measurement pupil 93, 94. Are configured to receive the light fluxes arriving at the respective microlenses 10. The arrangement direction of the focus detection pixels is made to coincide with the arrangement direction of the pair of distance measuring pupils (93, 94), that is, the arrangement direction of the pair of photoelectric conversion units (13, 14).

  The microlens 10 is disposed in the vicinity of the planned imaging plane of the interchangeable lens 202 (see FIG. 1). As described above, the shapes of the openings 30b and 30c that are close to the photoelectric conversion units 13 and 14 by the microlens 10 are formed. Projection is performed on the exit pupil 90 separated from the microlens 10 by the distance measurement pupil distance d, and the projection shape forms distance measurement pupils 93 and 94.

  The photoelectric conversion unit 13 outputs a signal corresponding to the intensity of the image formed on the microlens 10 by the light beam 73 passing through the distance measuring pupil 93 and directed to the microlens 10 of the focus detection pixel 313. Further, the photoelectric conversion unit 14 outputs a signal corresponding to the intensity of the image formed on the microlens 10 by the light flux 74 that passes through the distance measuring pupil 94 and travels toward the microlens 10 of the focus detection pixel 314.

  A large number of the two types of focus detection pixels described above are arranged in a straight line, and the output of the photoelectric conversion unit of each pixel is grouped into a distance measurement pupil 93 and an output group corresponding to the distance measurement pupil 94, thereby measuring the distance measurement pupil 93 and the measurement pupil 93. Information on the intensity distribution of the pair of images formed on the pixel array by the focus detection light beams that respectively pass through the distance pupil 94 is obtained. By applying an image shift detection calculation process (correlation calculation process, phase difference detection process), which will be described later, to this information, an image shift amount of a pair of images is detected by a so-called pupil division type phase difference detection method. Furthermore, by performing a conversion calculation according to the proportional relationship between the distance between the center of gravity of the pair of distance measurement pupils and the distance measurement pupil distance to the image shift amount, the current image formation surface (the position of the microlens array) ( The deviation (defocus amount) of the actual imaging plane at the focus detection position determined on the imaging screen is calculated.

  FIG. 16 is a diagram for explaining the state of the imaging light beam received by the imaging pixel 310 of the imaging device 212 shown in FIG. 7 in comparison with FIG. 15, and description of portions overlapping with FIG. 15 is omitted. The imaging pixel 310 includes the microlens 10 and the photoelectric conversion unit 11 disposed behind the microlens 10. The shape of the opening 30 a disposed in the vicinity of the photoelectric conversion unit 11 is the distance pupil distance d from the microlens 10. The projected image 90 is projected onto the spaced exit pupil 90, and the projected shape forms a region 95 that is substantially circumscribed by the distance measuring pupils 93 and 94. The photoelectric conversion unit 11 outputs a signal corresponding to the intensity of the image formed on the microlens 10 by the imaging light flux 71 that passes through the region 95 and travels toward the microlens 10.

  FIG. 17 is a flowchart showing the imaging operation of the digital still camera 201. When the power of the digital still camera 201 is turned on in step S100, the body drive control device 214 starts an imaging operation after step S110. In step S110, the data of the imaging pixel 310 is read out and displayed on the electronic viewfinder. In subsequent step S120, a pair of image data corresponding to the pair of images is read from the focus detection pixel array. It is assumed that the photographer has previously selected a desired focus detection pixel array on the imaging surface using a focus detection area selection member (not shown).

  In step S130, an image shift detection calculation process (correlation calculation process, phase difference detection process) described later is performed based on the read pair of image data, and the image shift amount is calculated and converted into a defocus amount. In step S140, it is checked whether or not the focus is close, that is, whether or not the calculated absolute value of the defocus amount is within a predetermined value. If it is determined that the lens is not in focus, the process proceeds to step S150, the defocus amount is transmitted to the lens drive controller 206, and the focusing lens 210 of the interchangeable lens 202 is driven to the focus position. Then, it returns to step S110 and repeats the operation | movement mentioned above.

  Even when focus detection is impossible, the process branches to this step, a scan drive command is transmitted to the lens drive control device 206, and the focusing lens 210 of the interchangeable lens 202 is driven to scan from infinity to the nearest. Then, it returns to step S110 and repeats the operation | movement mentioned above.

  If it is determined in step S140 that the focus is close, the process proceeds to step S160, and it is determined whether or not a shutter release has been performed by operating a shutter button (not shown). If it is determined that the shutter release has not been performed, the process returns to step S110 and the above-described operation is repeated. On the other hand, if it is determined that the shutter release has been performed, the process proceeds to step S170, where an aperture adjustment command is transmitted to the lens drive control unit 206, and the aperture value of the interchangeable lens 202 is set to the control F value (F set by the photographer or automatically). Value). When the aperture control is completed, the image sensor 212 is caused to perform an imaging operation, and image data is read from the imaging pixels of the image sensor 212 and all focus detection pixels.

  In step S180, pixel data of each pixel position in the focus detection pixel column is subjected to pixel interpolation based on data of the imaging pixels 310 around the focus detection pixels 313 and 314. In subsequent step S190, image data composed of the data of the imaging pixel 310 and the interpolated data is stored in the memory card 219, and the process returns to step S110 to repeat the above-described operation.

  Details of the image shift detection calculation process (correlation calculation process, phase difference detection process) in step S130 of FIG. 17 will be described below.

In the pair of images detected by the focus detection pixels 313 and 314, the distance measurement pupils 93 and 94 may be displaced by the aperture of the lens and the light amount balance may be lost. A type of correlation operation that can maintain the above is applied. Based on the patent application of the present applicant for a pair of data strings (A1 ₁ ,..., A1 _M , A2 ₁ ,..., A2 _M : M is the number of data) read out from the focus detection pixel string. Correlation calculation is performed according to the equation (2) disclosed in Japanese Unexamined Patent Application Publication No. 2007-333720 to calculate the correlation amount C (k).
C (k) = Σ | A1 _n · A2 _{n + 1 + k−} A2 _{n + k} · A1 _{n + 1} | (2)

In equation (2), the Σ operation is accumulated for n. The range taken by n is limited to a range in which data of A1 _n , A1 _{n + 1} , A2 _{n + k} , A2 _{n + 1 + k} exists according to the image shift amount k. The image shift amount k is an integer and is a relative shift amount with the data interval of the data string as a unit.

As shown in FIG. 18A, the calculation result of the expression (2) indicates that the correlation amount C (k) is obtained when the pair of data has a high correlation amount (k = k _j = 2 in FIG. 18A). Minimal (the smaller the value, the higher the degree of correlation). A shift amount x that gives a minimum value C (x) when the correlation amount is regarded as a continuous value is obtained using the three-point interpolation method according to equations (3) to (6).
x = k _j + D / SLOP (3)
C (x) = C (k _j ) − | D | (4)
D = {C (k _j −1) −C (k _j +1)} / 2 (5)
SLOP = MAX {C (k _j +1) −C (k _j ), C (k _j −1) −C (k _j )} (6)

  Whether the shift amount x calculated by the equation (3) is reliable is determined as follows. As shown in FIG. 18B, when the degree of correlation between a pair of data is low, the value of the minimum value C (x) of the interpolated correlation amount increases. Therefore, when C (x) is equal to or greater than a predetermined threshold, it is determined that the reliability of the calculated shift amount x is low, and the calculated shift amount x is canceled. Alternatively, in order to normalize C (x) with the contrast of data, when the value obtained by dividing C (x) by SLOP that is proportional to the contrast is equal to or greater than a predetermined value, the reliability of the calculated shift amount x The calculated shift amount x is cancelled.

Alternatively, if SLOP that is proportional to the contrast is equal to or smaller than a predetermined value, it is determined that the subject has low contrast and the reliability of the calculated shift amount x is low, and the calculated shift amount x is canceled. . As shown in FIG. _18C , when the correlation between the pair of data is low and there is no drop in the correlation amount C (k) between the shift range _kmin and _kmax , the minimum value C (x) is obtained. In such a case, it is determined that the focus cannot be detected. When it is determined that the calculated shift amount x is reliable, it is converted into the image shift amount shft by the equation (7).
shft = PY · x (7)

In Expression (7), PY is twice the pixel pitch (detection pitch) of the focus detection pixels 313 and 314. The image shift amount calculated by Expression (7) is multiplied by a predetermined conversion coefficient Kd to convert to the defocus amount def as expressed in Expression (8).
def = Kd · shft (8)

  FIG. 19 is an enlarged view of a region D in which the horizontal and vertical focus detection pixel arrays are close to each other in the image sensor 212 shown in FIG. Details of a method of calculating image data interpolated at the focus detection pixel position in step S180 in FIG. 17 will be described. In FIG. 19, focus detection pixels are arranged at shaded positions (originally the arrangement where G pixels and B pixels should be arranged). The subscript of each pixel is a number indicating a row and a column with the B pixel at the upper left as a base point, and symbols R, G, and B are imaging pixels 310, which are a red pixel (R) and a green pixel (G), respectively. , Blue pixel (B).

In FIG. 19, a part of the vertical focus detection pixel array sandwiched between rows of alternately arranged red pixels and green pixels is located in the central portion of FIG. The interpolated imaging signal averages the pixel data of the imaging pixels located adjacent to two pixels in the left and right horizontal directions, that is, the pixel data of green pixels or blue pixels. Accordingly, in the vertical focus detection pixel array, _assuming that the image pickup signal interpolated at the position of the p-th row and the q-th column is V _pq , when the image pickup pixel used for the averaging is a green pixel, Expression (9) In the case where the imaging pixel used for the averaging is a blue pixel, it is expressed by Expression (10).
_Vpq = { _{Gp (q-2)} + _{Gp (q + 2)} } / 2 (9)
_Vpq = { _{Bp (q-2)} + _{Bp (q + 2)} } / 2 (10)

According to the equation (9), the interpolation value of the imaging signal V ₂₅ at the position of the second row and the fifth column is obtained as an average of G ₂₃ and G _27. According to the equation (10), the third row The interpolated value with the imaging signal V _{35 at} the position in the fifth column is obtained as an average of B ₃₃ and B ₃₇ .

In FIG. 19, a part of the horizontal focus detection pixel array sandwiched between rows in which red pixels and green pixels are alternately arranged is located at both the left and right ends of FIG. The interpolated imaging signal averages the pixel data of the imaging pixels located adjacent to two pixels in the vertical direction, that is, the pixel data of green pixels or blue pixels. Therefore, in the horizontal focus detection pixel array, _assuming that the imaging signal to be interpolated at the position of the p-th row and the q-th column is H _pq , when the imaging pixel used for the averaging is a green pixel, Expression (11) In the case where the image pickup pixel used for the addition average is a blue pixel, it is expressed by Expression (12).
_Hpq = {G _{(p-2) q} + G _{(p + 2) q} } / 2 (11)
_Hpq = {B _{(p-2) q} + B _{(p + 2) q} } / 2 (12)

According to equation (11), the imaging signal _{H 38} of the position of the third row eighth _column, determined as the arithmetic mean of _{G 18} and _{G 58,} according to the equation (12), third row 9 column imaging signals _{H 39} position _is determined as the arithmetic mean of _{B 19} and _{B 59.}

The horizontal and vertical focus detection pixel arrays having the same length are separated from each other with two image pickup pixels sandwiched therebetween, for example, B ₃₃ and G ₃₄ so as not to be in complete contact with each other. Therefore, the interpolated value of the imaging signal V ₃₅ at the position of the third row and fifth column is the addition of B ₃₃ and B ₃₇ which are pixel data of the imaging pixels closest to the focus detection pixel array in the same color imaging pixels. Since it is obtained as an average, the performance of pixel interpolation processing is improved.

--- Second Embodiment ---
In the imaging device 212 illustrated in FIG. 7, an example in which each pixel includes a pair of focus detection pixels 313a and 314a and a pair of focus detection pixels 313b and 314b each having one photoelectric conversion unit is illustrated. A pair of photoelectric conversion units may be provided. FIG. 20 is a partially enlarged view of such an image sensor 212. The focus detection pixels 311a and 311b each include a pair of photoelectric conversion units.

  The focus detection pixel 311a illustrated in FIG. 21 performs a function corresponding to the pair of the focus detection pixel 313 and the focus detection pixel 314 illustrated in FIGS. The focus detection pixel 311 includes a microlens 10 and a pair of photoelectric conversion units 13 and 14 as shown in FIG. The focus detection pixel 311 is not provided with a color filter in order to increase the amount of light, and its spectral characteristic is a spectral that combines the spectral sensitivity of a photodiode that performs photoelectric conversion and the spectral characteristic of an infrared cut filter (not shown). Characteristics (see FIG. 12). That is, the spectral characteristics are obtained by adding the spectral characteristics of the green pixel, the red pixel, and the blue pixel shown in FIG. 10, and in the light wavelength region showing high spectral sensitivity, the green pixel, red pixel, and blue pixel show high spectral sensitivity. It covers the optical wavelength region. The focus detection pixel 311 is a general term for the focus detection pixels 311a and 311b.

  FIG. 22 is a cross-sectional view of the focus detection pixel 311 shown in FIG. 21, in which a light shielding mask 30 is formed in proximity to the photoelectric conversion units 13 and 14, and the light beam conversion units 13 and 14 are connected to the light shielding mask 30. The light that has passed through the opening 30d is received. A planarizing layer 31 is formed on the light shielding mask 30, and an ND filter 34 is formed thereon. A planarizing layer 32 is formed on the ND filter 34, and the microlens 10 is formed thereon. The shape of the photoelectric conversion units 13 and 14 limited to the opening 30d by the microlens 10 is projected forward to form a pair of distance measuring pupils. The photoelectric conversion units 13 and 14 are formed on the semiconductor circuit substrate 29.

  Since the imaging operation of the digital still camera 201 and the accompanying pixel interpolation processing, image shift detection calculation processing, and focusing operation are the same as those in the first embodiment, description thereof is omitted.

---- Modified example ---
In the first embodiment of the present invention, the plain weave pattern, which is an aspect of the arrangement of the focus detection pixel array, is perpendicular to the horizontal focus detection pixel array whose long sides are the same length as shown in FIG. The direction focus detection pixel array is arranged at high density. However, the direction of the long side of the focus detection pixel array is not limited to the combination of the horizontal direction and the vertical direction. A pair of focus detection pixel arrays in the two directions whose long sides are the same length (the first array or the second array described above) do not cross each other and maintain a vertical relationship, and the first array and the second array May be another mode in which the positions are symmetrically arranged with respect to each other. Alternatively, another set of focus detection pixel arrays extending in the vertical direction from one side of a pair of focus detection pixel arrays in two directions whose long sides are the same length may be used. An aspect may be sufficient. Furthermore, another mode in which any one of the first array and the second array described above is repeatedly arranged over the front surface of the imaging surface may be employed. Some of these aspects are described below.

(1) In FIG. 6, one set of focus detection pixel arrays is arranged in a row in the horizontal direction and in the vertical direction with one focus detection pixel array as a unit column. On the other hand, in FIG. 23, the unit row is replaced with two parallel focus detection pixel arrays to form a set of focus detection pixel arrays, thereby forming a plain weave pattern. By adding the corresponding focus detection pixels (top and bottom or left and right adjacent focus detection pixels) in the two parallel rows of focus detection pixel arrays, the focus detection pixel output level at low luminance is increased, and low luminance performance is improved. Can be improved.

(2) In FIG. 6, each of a plurality of filled areas formed by being surrounded by the nine focus detection pixel arrays marked with the circles noted in FIG. 5C is represented by S _{1 to} S ₄ . In this case, the sum of the areas is S = L ² as described above. FIG. 24 shows focus detection in FIG. 6 so that the outer shapes of the regions S ₁ and S ₄ are rectangular and the outer shape of the region S ₂ is a small square while maintaining the relationship of S = L ² . A plain weave pattern formed by moving the pixel array is shown. In this plain weave pattern, a plurality of horizontal focus detection pixel arrays are arranged at equal intervals in the horizontal direction and sandwich a plurality of vertical focus detection pixel arrays. Furthermore, a plurality of vertical focus detection pixel arrays are arranged at equal intervals in the vertical direction and sandwiching the plurality of horizontal focus detection pixel arrays. The distance between one focus detection pixel array included in a plurality of horizontal focus detection pixel arrays and the focus detection pixel array arranged in parallel adjacent to one side thereof is the focus detection pixel array and the other side. Is different from the distance from the focus detection pixel array that is arranged adjacent to and in parallel. Hereinafter, FIG. 24 will be described in detail.

In FIG. 24, the distance between the focus detection pixel column sandwiched between the regions S ₁ and S ₂ and the regions S ₃ and S ₄ and the focus detection pixel column arranged in parallel adjacent to the upper side is as follows. Smaller than the distance between the focus detection pixel row sandwiched between the regions S ₁ and S ₂ and the regions S ₃ and S ₄ and the focus detection pixel row arranged in parallel adjacent to the lower side thereof. . Similarly, the distance between the focus detection pixel column sandwiched between the regions S ₁ and S ₃ and the regions S ₂ and S ₄ and the focus detection pixel column arranged in parallel adjacent to the right side thereof is The distance is smaller than the distance between the focus detection pixel column sandwiched between the regions S ₁ and S ₃ and the regions S ₂ and S ₄ and the focus detection pixel column arranged in parallel adjacent to the left side thereof. By using the area S ₂ of the focus detection pixel array becomes dense arising as a default separate focus detection area, the focus detection performance (subject acquisition performance) of the focus detection area is increased.

(3) In FIG. 6, the horizontal and vertical focus detection pixel arrays are arranged equally and with the highest density. However, as shown in FIG. 5B, a mode in which the uniformity is slightly relaxed is also possible. It is. Figure 25 shows a similar manner to the embodiment shown in FIG. 5 (b), while the maintaining density of the rectangular congruent to the outer shape of the region S ₁ and S _4, the outer shape of the region S ₂ and S ₃ A plain weave pattern formed by forming squares of different sizes. By using the area S ₂ of the focus detection pixel array becomes dense arising as a default separate focus detection area, the focus detection performance (subject acquisition performance) of the focus detection area is increased.

(4) The arrangement direction of the focus detection pixel arrangement may be not only a combination of the vertical direction and the horizontal direction as shown in FIG. 4 but also a combination of a diagonally upward 45 degree direction and a diagonally upward 45 degree direction. Since the edge of the subject is often in the horizontal direction or the vertical direction, if the imaging position of the edge coincides with the position of the focus detection pixel array, the pixel output level difference of the edge may be reduced by pixel interpolation. This modification is effective in such a case.

  FIG. 26 is a diagram in which focus detection pixel arrays are arranged in a combination of an obliquely upward 45 degree direction and an obliquely upward 45 degree direction on the imaging surface of the imaging element 212. In FIG. 26, the focus detection pixel array having a long side length M is shown as a bar-like region 353 having a diagonally upward 45 ° direction and a bar-like region 354 having a diagonally upward 45 ° direction. 354 are arranged on a rectangular imaging surface according to a plain weave pattern. As a result, the horizontal focus detection pixel array and the vertical focus detection pixel array having the same long side are arranged in an even and dense manner under the condition that the arrays do not cross each other. The length of the focus detection pixel array can be made as long as possible.

  FIG. 27 is a front view showing a detailed configuration of the image sensor 212, and shows the details of the pixel arrangement by enlarging the vicinity of the portion C in FIG. Imaging pixels 310 are densely arranged on the imaging element 212 in a two-dimensional square lattice pattern. The imaging pixel 310 includes a red pixel (R), a green pixel (G), and a blue pixel (B), and is arranged according to a Bayer arrangement rule. For focus detection, focus detection pixels 313c, 314c for 45 ° direction focus detection, which have the same pixel size as the imaging pixels, alternately and focus detection pixels 313d for 45 ° direction focus detection, diagonally left upward, 314d are alternately arranged continuously on a straight line in the direction of 45 degrees obliquely where the green pixels should be continuously arranged. Since many green pixels are arranged according to the Bayer arrangement, it is preferable to replace the green pixel with the focus detection pixel rather than either the red pixel or the blue pixel because the influence on the pixel interpolation process is small.

  In a region where the two focus detection pixel arrays are close to each other, a terminal pixel of one focus detection pixel array (a focus detection pixel array in the 45 ° upward and leftward direction in FIG. 27) is arranged, and between the other focus detection pixel arrays An image pickup pixel (green pixel) is arranged in FIG. This improves the performance of the pixel interpolation process described above in the region where the two focus detection pixel arrays are close to each other.

  In the imaging device 212 in the above-described embodiment, the imaging pixel 310 includes the Bayer color filter, but the configuration and arrangement of the color filter are not limited to this, and the complementary color filter (green: G, The present invention can also be applied to arrays other than yellow: Ye, magenta: Mg, cyan: Cy) and Bayer arrays.

  In the focus detection pixels 311, 313, and 314 in the above-described embodiment, an example in which the opening shape of the light shielding mask 30 is rectangular has been described, but the opening shape of the light shielding mask 30 is not limited to these, and other shapes are used. For example, it may be a semicircle, an ellipse or a polygon.

  Note that the imaging apparatus is not limited to a digital still camera or a film still camera in which an interchangeable lens is mounted on the camera body as described above. For example, the present invention can be applied to a lens-integrated digital still camera, film still camera, or video camera. Furthermore, the present invention can be applied to a small camera module built in a mobile phone, a surveillance camera, a visual recognition device for a robot, an in-vehicle camera, and the like.

9, 10 Microlenses 11, 13, 14 Photoelectric conversion unit 29 Semiconductor circuit board 30 Light shielding mask 31, 32 Flattening layer 34 ND filter 38 Color filter 71 Imaging light beam 73, 74 Focus detection light beam 83, 84 Light beam 90 Exit pupil 91 Optical axis 93, 94 of the interchangeable lens 93 Distance pupil 95 Area 110 substantially circumscribing the distance pupil 110 Imaging surface 111 Focus detection pixel 112 Micro lens 113, 114 Photoelectric conversion unit 120 Distance pupil surface 123, 124 Distance pupil 133, 134 Distance pupil distribution 135 Superimposing portion 201 Digital still camera 202 Interchangeable lens 203 Camera body 204 Mount portion 206 Lens drive control device 208 Zooming lens 209 Lens 210 Focusing lens 211 Aperture 212 Imaging element 213 Electrical contact 214 Body drive control device 215 Liquid Crystal display element driving circuit 216 Liquid crystal display element 217 Eyepiece 219 Memory card 310 Imaging pixel 311, 313, 314 Focus detection pixel 351, 352, 353, 354 Focus detection pixel array

Claims (16)

A plurality of imaging pixels that receive an imaging light beam emitted by an optical system and form an optical image and output an image signal;
A plurality of focus detection pixels which receive a pair of focus detection light beams passing through the optical system and output a focus detection signal for detecting a focus adjustment state of the optical system by a pupil division type phase difference detection method; An imaging surface formed by the imaging pixels and the plurality of focus detection pixels,
The plurality of focus detection pixels constitute a plurality of focus detection pixel rows,
The plurality of focus detection pixel rows are arranged according to a plain weave pattern over substantially the entire imaging surface,
The imaging device, wherein the plurality of imaging pixels are arranged over substantially the entire imaging surface except for a pixel position where the plurality of focus detection pixels are arranged. The imaging device according to claim 1,
The plurality of focus detection pixel rows include a first focus detection pixel row extending in one direction and a second focus detection pixel extending in a vertical direction from one side of the first focus detection pixel row. A repeating array unit composed of columns and
The image pickup device according to claim 1, wherein the plain weave pattern is formed by repeatedly arranging the repeating arrangement unit without contacting. The imaging device according to claim 1,
The plurality of focus detection pixel rows include a first focus detection pixel row extending in one direction and a second focus detection pixel extending in a vertical direction from one side of the first focus detection pixel row. Arranged in a point-symmetric position with respect to the first and second focus detection pixel columns so as not to intersect the first and second focus detection pixel columns. A second array composed of third and fourth focus detection pixel rows,
The image pickup device according to claim 1, wherein the plain weave pattern is formed by repeatedly arranging a repeating array unit including the first array and the second array. The imaging device according to claim 1,
The imaging surface has a rectangular shape,
Each of the plurality of focus detection pixel rows has an equal length,
The plurality of focus detection pixel columns include a plurality of first focus detection pixel columns and a plurality of second focus detection pixel columns,
The pixel array direction of the plurality of first focus detection pixel columns is perpendicular to the pixel array direction of the plurality of second focus detection pixel columns,
The image sensor according to claim 1, wherein a pixel arrangement direction of the plurality of first focus detection pixel columns is the same as a direction of one side of the rectangle. The imaging device according to claim 4,
In the plain weave pattern, the plurality of first focus detection pixel columns are arranged at equal intervals in the pixel arrangement direction of the plurality of first focus detection pixel columns and sandwich the plurality of second focus detection pixel columns. Arranged,
Further, in the plain weave pattern, the plurality of second focus detection pixel rows are arranged at equal intervals in the pixel arrangement direction of the plurality of second focus detection pixel rows and sandwich the plurality of first focus detection pixel rows. An image pickup device characterized by being arranged as described above. The imaging device according to claim 5,
The plurality of focus detection pixel columns include a pair of parallel first focus detection pixel columns included in the plurality of first focus detection pixel columns and a plurality of second focus detection pixel columns. An image pickup device comprising: a pair of second focus detection pixel rows that are included and are adjacent to and parallel to each other. The imaging device according to claim 5,
The distance between one focus detection pixel row included in the plurality of focus detection pixel rows and the focus detection pixel row arranged in parallel adjacent to one side of the one focus detection pixel row is the one focus. An imaging device, wherein the distance between a detection pixel column and a focus detection pixel column arranged in parallel adjacent to the other side of the one focus detection pixel column is different. The imaging device according to claim 4,
The plain weave pattern includes the first focus detection pixel row in one of the plurality of first focus detection pixel rows and the one first focus detection in the plurality of second focus detection pixel rows. At least two focus detection pixel columns constituted by one second focus detection pixel column that is closest and perpendicular to the pixel column are defined as unit pixel columns, and the unit pixel columns are evenly arranged on the imaging surface. The plurality of first focus detection pixel rows and the plurality of second focus detection pixel rows are arranged so that two types of squares having different sizes are formed by being repeated. An imaging device as a feature. The imaging device according to claim 1,
The imaging surface has a rectangular shape,
Each of the plurality of focus detection pixel rows has an equal length,
The plurality of focus detection pixel columns include a plurality of first focus detection pixel columns and a plurality of second focus detection pixel columns,
The pixel array direction of the plurality of first focus detection pixel columns is perpendicular to the pixel array direction of the plurality of second focus detection pixel columns,
The image pickup device according to claim 1, wherein a pixel arrangement direction of the plurality of first focus detection pixel columns is the same as a direction that forms 45 degrees with one side of the rectangle. The imaging device according to any one of claims 4 to 8,
The imaging element, wherein the first focus detection pixel array and the second focus detection pixel array are arranged with the plurality of imaging pixels interposed therebetween. In the imaging device according to any one of claims 1 to 10,
The imaging device, wherein the plurality of imaging pixels are arranged in a square lattice pattern. The imaging device according to claim 11,
The plurality of imaging pixels include a red pixel, a green pixel, and a blue pixel,
2. The imaging device according to claim 1, wherein the square lattice array is a Bayer array formed by the red pixels, the green pixels, and the blue pixels. The imaging device according to any one of claims 1 to 9,
Each of the plurality of focus detection pixels includes a microlens and a photoelectric conversion unit provided corresponding to the microlens,
The plurality of focus detection pixels include a first focus detection pixel that receives one of the pair of focus detection light beams and a second focus detection pixel that receives the other of the pair of focus detection light beams. Including
The imaging element, wherein the first focus detection pixels and the second focus detection pixels are alternately arranged in each of the plurality of focus detection pixel rows. The imaging device according to any one of claims 1 to 9,
Each of the plurality of focus detection pixels includes a microlens and a first photoelectric conversion unit and a second photoelectric conversion unit provided corresponding to the microlens,
The first photoelectric conversion unit receives one of the pair of focus detection light beams, and the second photoelectric conversion unit receives the other of the pair of focus detection light beams. An image sensor. Optical system,
The image sensor according to any one of claims 1 to 14,
Generating means for generating image data based on the image signal obtained from the image sensor;
An imaging apparatus comprising: a focus detection unit configured to detect a focus adjustment state of the optical system based on the focus detection signal obtained from the image sensor. Optical system,
The image sensor according to claim 10,
Interpolation means for interpolating an interpolation signal at a pixel position where the plurality of focus detection pixels are arranged based on the image signal output from the plurality of imaging pixels in the vicinity of the pixel position;
Generating means for generating image data based on the image signal obtained from the image sensor and the interpolation signal at the pixel position to be interpolated by the interpolation means;
A focus detection unit that detects a focus adjustment state of the optical system based on the focus detection signal obtained from the image sensor;
The plurality of imaging pixels arranged between the first focus detection pixel column and the second focus detection pixel column in the image signal output from the plurality of imaging pixels in the vicinity of the pixel position An image pickup apparatus characterized in that the image signal output from is included.

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